Normally, the length to diameter ratio of rotary dryers varies from 4 to 10 and for its economic operation; the number of transfer units (NTU) for such dryers varies from ?
Correct answer: A
Explanation
For economic operation of rotary dryers with a length to diameter ratio of 4 to 10, the typical range for transfer units (NTU) is 1.5 to 2.5.